Over a century and a half ago, Charles Darwin first described the remarkable adhesive capabilities of barnacles. He couldn't figure out how their natural superglue worked, though. And it took until now to finally unlock the barnacle glue's mysteries.

It's actually surprisingly simple. The key to the super sticky cement barnacles create is actually the tiny drop of oil that their larvae release before attaching to a surface. This droplet clears the water from the surface, enabling them to lay down a phosphoprotein adhesive. Previously, scientists thought that the two substances mixed together to create a bond, but now it's clear that the oil and the adhesive serve two very distinct roles.

"It's an incredibly clever natural solution to this problem of how to deal with a water barrier on a surface," said Dr. Nick Aldred, who authored a paper on the breakthrough that was published in Nature Communications this week. "It will change the way we think about developing bio-inspired adhesives that are safe and already optimized to work in conditions similar to those in the human body, as well as marine paints that stop barnacles from sticking."

Medical applications for nature's strongest superglue are exciting, but they're also a ways off. At the very least, the shipping industry can use the new knowledge to figure out how to get all those damned barnacles off the bottom of boats. The increased drag the arthropods create costs an estimated $7.5 billion in wasted fuel every year. [Nature]